Embodiments of the invention relate to a system and a method for improving engines operating at a stoichiometric condition. More particularly, embodiments of the invention relate to an engine controller and related methods for controlling an emission amount in a gas stream emitted from a power generation system employing an engine operating at the stoichiometric condition.
Internal combustion (IC) engines are used in a wide range of applications. The IC engines use a variety of fuels including, but not limited to, liquid fuels such as gasoline (sometimes referred to as petrol) and diesel, and gaseous fuels such as liquefied natural gas (LNG) or liquefied petroleum gas (LPG). Typically, combustion of such fuels in an IC engine produces by-products that are discharged from the IC engine in the form of a gas stream. The exhaust gas stream from the IC engine may include contaminants, such as, oxides of nitrogen (NOx), carbon monoxide (CO), hydrocarbons (HC), or combinations thereof. Such contaminants, when mixed into the atmosphere, may lead to various environmental hazards.
Typically, in order to minimize levels of the contaminants (sometimes referred to as emission levels) in the gas stream, the IC engines operating at stoichiometric condition may employ a three-way catalyst. The three-way catalyst causes chemical reactions such as, but not limited to, oxidation and reduction, to treat the gas stream in order to minimize the levels of the contaminants. Further, use of an exhaust gas recirculation (EGR) along with the use of the three-way catalyst may help in minimizing levels of the contaminants.
However, in order to consistently achieve low levels of the contaminants in the exhaust gas stream, it may be desirable to maintain operation of the IC engine at the stoichiometric condition. Maintaining the stoichiometric condition during the operation of the IC engine may be a challenge. Further, maintaining low levels of the contaminants as the IC engine and the three-way catalyst ages, may be another challenge. Furthermore, when the IC engine is employed in a mobile application, it may also be desirable that the levels of the contaminants are maintained to meet emission requirements of a given region. Thus, there is a need for improved methods and related controllers and power generation systems to maintain the emission levels in the exhaust stream.